Fluid cushion



Patented July 18, 1933 UNITED STATES PATENT OFFICE WARREN DOBLE, OF EMERYVILLE, CALIFORNIA, ABSIGNOR TO DOBLE STEAM MOTORS CORPORATION, OF WILMINGTOIL DELAWABE, A CORPORATION OF DELAWARE FLUID CUSHION Application filed October 30', 1929. Serial No. 403,494.

My invention relates to fluid cushions for use with fluid handling means wherein conditions arise which cause that vibration which is termed hammering to occur. More particularly my invention relates to a steam or vapor generator such asa steam boiler wherein. upon the introduction of fluid such as water into the generator, the occurrence of hammering is obviated by the provision of fluid cushioning means.

It is an object of my invention to provide for the cushioning of the fluid introduced into a generator upon the operation of the means which supplies fluid.

Another object of my invention is to provide means for obviatin water hammer upon the introduction of Iced water into a boiler.

A further object of my invention is to provide for the cushioning of the feed water introduced into a boiler by the provision of cushioning means in which steam generated by the heat of the boiler is utilized as the cushion. An additional object of my invention is to provide a cushion to prevent liquid hammer in a liquid line subject to pulsations.

A still further object of my invention is to provide in a liquid line in which there is a source of pulsations, a cushion adjacent the source to preclude liquid hammer in the line.

My invention possesses other advantageous features, some of which with the foregoing will be set forth at length in the following description where I shall outline in full that.form of steam'generator employing a fluid cushion of my invention, which I have selected for illustration in the drawing accompanying and forming part of the present specification. In said drawing I have shown one form of fluid cushion embodying my invention but it is to be understood that I do not limit myself to such form since the invention, as set forth in the claims, may be embodied in a plurality of forms.

In the drawing, Figure 1 is a schematic representation of a boiler employing the fluid cushion of my invention.

Figure 2 is a diagrammatic showing of another form of fluid cushion of my invention.

In the form of my invention which I am here disclosing I have preferably employed a steam boiler by way of illustration. However, my invention is applicable to other steam or vapor generators and to other fluids than water. Accordingly, I do not Wish to be limited solely to the illustration em loyed.

n that form of my invention which is particularly illustrated in Fig. 1 of the drawing I have shown a boiler 6 of the series tube or forced circulation type as comprising a relatively. long coiled tube 7. A casing 8, which includes suitable heat insulating material 9, is provided about the tube so that the heat supplied from burner 11 is largely utilized only for the purpose of generating steam. The burner 11 usually comprises a suitable carbureting device 12 in combination with air supply means 13. Upon ignition of the carbureted fuel the resulting products of combustion traverse about the tube 7 and are finally discharged thru outlet 14.

I have preferably illustrated the tube as having an inlet 16 adjacent to the discharge of the products of combustion from the burner and a discharge 17 adjacent to the inlet of the products of combustion so that a counterflow of fluid to be heated with respect to the productsiof combustion is provided for.

Feed water supplied by suitable means as reciprocating pump 21 is introduced from a suitable source of supply (not shown) -thru the inlet 16 to the tube 7. A check valve 22 is preferably interposed. between the inlet and the pump21 so that discharge of generated steam will not occur thru the pump. To control the emission of steam a control valve 23 is provided in the discharge 17of the tube.

Upon an operation of the feed water supply pump the relatively long column of water confined in the boiler and in the pipe communicating with the boiler is set in motlon. Upon each stroke of delivery of the pump this long column of water is retarded and accelerated, thus causing hammering to occur. I have found this condition even when a plurality of pumps are employed and are positioned close to the boiler. The effect of hammering upon the boiler is undesirable, particularly because of the resulting high stresses occasioned by the oscillation of the column back and forth and the undue noise. In certain types of steam generators such as a flash boiler, as I have here illustrated, or in stills and other equipment where a relatively long body of fluid is confined the length of the column which is effected by the introduction of fluid cannot be reduced below a predetermined set value.

In accordance with my invention I propose to provide a suitable chamber 31 in communication with the fluid supply nunip' and with the boiler so that the introduction of fluid is cushioned. As a cushion I prefer that the vapor of the fluid being supplied to the boiler be utilized. Thus, in the preferred form which I am here illustrating, water has been supplied to the chamber 31 some of which is converted into steam by a suitable source of heat to act'as the cushion. As is shown in the drawing, I prefer that the chamber 31 be formed of a relatively short length of tubing, an end 32 of which is in communication with the discharge of the feed water, supply pump and with the inlet 16 of the boiler and the other end 33 of which is sealed. I further prefer that the chamber be subjected to a source of heat so that the water therein be converted into steam which will act as a cushion. Conveniently I have inserted the chamber adjacent to the coils of the tube 7 -within the heating space of the boiler so that the products of combustion pass over it and supply heat to it. I have also found it desirable in most instances to position the chamber in such a manner that a relatively large continuous fluid cushion is formed. Thus, as is shown in the drawing, the chamber is positioned with the sealed end 33 uppermost with respect to the inlet end 32 so that steam will collect there.

Upon operation of the boiler, the heat supplied to the fluid cushioning means will generate and will maintain a pocket of steam within the cushioning means substantially at all times during the operation of the boiler. I prefer that the fluid being utilized in the boiler be employed as the cushioning means inasmuch as I.have found that it is the most conveniently provided and most readily maintained fluid.

Upon operation of the feed water supply pump, the steam generated in the chamber 31 providesa readily contractable and exp'andible body which will serve to dampen out the oscillatory effect of the feed Water supply pump.

Special care need not be taken in supplying fluid to the chamber when beginning operations with a generator employing my invention since the air contained in the chamber will soon become dissolved in the fluid or be otherwise removed whereupon the water or other fluid will enter into the chamber.

In that form of my invention which is shown in Fig. 2 the fluid cushioning chamber 31 is provided about conduit 36 which leads from the control valve 23 to a means for utilizing the generated vapor, as engine 37. The heat'of the vapor passes thru the conduit 36 to the chamber 31 to generate the cushioning vapor. I have found it desirable to form the chamber adjacent to the conduit and to enclose the chamber and conduit with a suitable heat insulating material.

In operation with a form of my invention I have supplied the usual motive power for the pump 21 from the engine 37 so that the pump was actuated in normal operation only when steam was being delivered to the engine. This manner of operation makes the creation of the fluid cushioning chamber a substantially automatic one.

I claim:

1. In a vapor generator, means for heating said generator, pulsating means for .introducing fluid into said generator, means for containing fluid in communication with said introducing means and close to the inlet of said generator, said containing means being subject to heat to generate vapor therein.

2. In a vapor generator, pulsating means for supplying fluid to said generator, and vapor confining means in communication with the inlet portion of said generator and close to said pulsating means, said vapor confining means being adapted to receive heat whereby vapor is generated therein to cushion the introduction of fluid into said generating means.

3. In a boiler comprising a relatively long tube into one end of which is pumped feed fluid subject to pulsations and from the other end of which steam issues, a chamber communicating with the feed end of said tube close to the source of said pulsations, and means for heating said chamber to generate steam therein.

4. A fluid cushion comprising a tube containing liquid subject to pulsations, a chamber connected to said tube close to the source of aid pulsations and containing said fluid,

and means for vaporizing fluid in said chamber to act as a vapor cushion.

5. In a fluid pumping system, a pulsating fluid pump, a fluid receptacle, a tube for conveying fluid under pressure from said pump to said receptacle, and a heated chamber in communication with said tube close to said pump, said chamber containing the vap from said boiler,

por of said fluid to act as a fluid cushion for said pump.

6. In a steam boiler plant, a pulsating water pump, a steam boiler, a feed water tube for conveying feed water under pressure from said pump to said boiler, a superheated steam pipe for conveying superheated steam away from said boiler, and a chamber communicating with said feed water tube and in thermal contact with said steam pipe so that feed water in said chamber is converted into steam and acts as a fluid cushion for water introduced in the boiler.

7. A fluid cushion comprising a feed in.- let pipe for a boiler, a pulsating pump for forcing liquid into said pipe, an otherwise closed chamber communicating with said pipe close to said pumps, and means for generating the vapor of said liquid in said chamber.

8. A fluid cushion comprising a liquid supply pipe, a pulsating pump 'for forcing liquid into said pipe, means for heating said liquid to form a superheated vapor, a superheated vapor discharge pipe, and a chamber physically communicating with said supply pipe and thermally communicating with said discharge pipe.

9. A fluld cushion comprising a feed inlet pipe for conducting pulsating feed fluid to a boiler, a,superheated vapor outlet pipe and a chamber physically communicating with said inlet pipe and thermally communicating with said outlet pipe.

10. A fluid cushion comprising a relatively long boiler tube, a feed inlet pipe connected to one end of said tube for conducting pulsating feed fluid thereto, a superheated vapor outlet pipe connected to the other end of said tube, and a conduit coiled around said outlet pipe, one end of said conduit being closed and the other end of said conduit being open to said inlet pipe.

11. A fluid cushion comprising a relatively long boiler tube, a water inlet pipe connected to one end of said tube, a pulsating pump for forcing water into said inlet pipe, a superheated steam outlet pipe connected to the other end of said tube, and a conduit having one end closed and the other end communicating with said inlet pipe, said conduit being in thermal communication with said steam outlet.

12. A fluid cushion comprisi a liquid supply pipe, a pulsating pump or forcing liquid into said pipe, an otherwise closed chamber communicating with said ipe close to said pump and means for estab 'shing a volume of the vapor of said liquid in said chamber.

13. A fluid cushion comprising a liquid pipe, a pulsating pump for forcing liquid into said pipe, a chamber communicating with said pipe near said pump, and means for maintaining a volume of vapor in said chamber.

14. In a vapor generator, a. fluid contain er, means for forcing a pulsating flow of fluid into the container, and a chamber communicating with said forcing means ad'acent the outlet thereof and containing t e vapor of said fluid to act as a cushion.

15. In a va r generator, pulsating means for forcing uid into the generator, and a chamber in communication with said forcing means adjacent the connection thereof with said generator containing the vapor of said fluid acting as a fluidcushion.

16. In a boiler having a feed water pipe in which there is a flow of water subject to pulsations, a chamber communicating with said feed water pipe close to the source of said pulsations, and means for heating said chamber sufficiently to generate steam in said chamber to act as a cushion for water introduced into the boiler through said feed water ipe.

17. pparatus of the character described comprising a tube, a source of pulsating liquid flowin said tube, and means communicating with said tube near said source and contalning the vapor of said liquid to act as a cushion for said pulsations.

18. Apparatus of the character described comprising a tube, a source of pulsating liquid flow in said tube, and a chamber communicating with said tube near said source and being subject to heat to vaporize liquid in said chamber.

19. Apparatus of the character described comprising a tube, a reciprocating pump for forcing liquid through said tube, and means for confining a body of vapor of said fluid in communication with said tube adjacent said pump to act as a vapor cushion.

WARREN DOBLE. 

